1. Field of the Invention
The invention relates generally to the field of optical and electronic sighting systems.
More specifically, the invention relates to an opto-electronic sighting or targeting system comprising a fixed alignment frame in cooperation and a laser illumination element to provide precision electronic positioning of an electronic reticle in a target area with respect to the alignment frame aperture.
2. Description of the Related Art
Prior art targeting sighting and reticle alignment systems such as are found in weapons sighting systems generally comprise an optical magnification system comprised of a series of optical lens elements with a reticle or “cross-hair” pattern provided such that the reticle is superimposed in an observer's field of view as seen through the eyepiece of sighting system.
When the optical targeting sighting system, which may comprise a telescopic sight or “scope”, is properly fitted and aligned on, for instance, the barrel of a weapon, the alignment of the elements of the reticle with an object in the field of view (e.g., a target) will closely approximate the location where the projectile will strike.
It is common that conventional optical targeting sighting systems are provided with a mechanical X-Y adjustment means to permit small incremental adjustments in the position of the reticle pattern with respect to the muzzle of the weapon barrel.
The development of image intensification (“I2”) and thermal imaging technologies has led to advances in weapon sights that provide the viewer with the ability to see a target in low-light and no-light environments.
Of particular value in no-light environments such as darkened buildings or caves or in smoke or dust obscured environments is the use of thermal imaging weapons sights. Thermal sighting systems that are sensitive to a region or multiple regions of the infrared spectrum (i.e., NIR, SWIR, MWIR, LWIR and FIR from about 0.75 to about 1000 micron wavelengths) are well-suited to the above low-light, low-visibility environments in that they permit a user to see heat differences or reflected infrared energy by sensing predetermined ranges of infrared spectra from objects in a scene of interest rather than relying on reflected light in the visible spectrum.
Infrared sensors, typically two-dimensional arrays of detector pixel elements in the form of focal plane arrays or “FPAs”, are used for infrared imaging and are sensitive to defined bands of the electromagnetic spectrum, such as the LWIR and SWIR infrared bands, each of which has different electrical responses to different lighting environments. For instance, LWIR detectors are well suited to no-light and very low light environments while SWIR detectors provide useful outputs at dusk where there is some sunlight remaining, partially due to naturally-occurring atmospheric night glow or air glow created by hydroxyl ion emissions.
Accordingly, a multi-spectral targeting sight that provides an LWIR and SWIR display output is desirable for around-the-clock use without the need to reconfigure or replace the sight on the weapon. A SWIR/LWIR multi-color focal plane array rifle sight is desirable to provide 24/7 operation that automatically adjusts for varying environmental and viewing conditions through the integration of a digital signal processor within the rifle sight to ensure optimum control and operability and to provide wide spectral transmission (e.g., about 0.5-about 12.0 microns).
Unfortunately, prior art thermal sighting systems that have an electronically-generated reticle superimposed on the target image are prone to drift due to temperature, vibration or shock or other environmental factors. Performance effectiveness of prior art sighting systems, and rifle sighting systems in particular, is limited by the inability to operate in day, twilight and night conditions without significant, impractical reconfiguration.
Sighting system accuracy, and thus lethality, is degraded by environmentally-induced “drift” in aiming quality caused by such factors such as temperature and humidity changing the performance of electro-optical and alignment elements. Uncompensated crosswind velocity further degrades lethality.
The above deficiencies in the prior art coupled with the fact such systems generally comprise an imager that is sensitive to a single spectrum on the infrared region create a need for a self-calibrating, multi-spectral weapons sight.